The overall objectives of this project are to characterize and compare the pathophysiology and pharmacological responses of myasthenia gravis and experimental autoimmune myasthenia gravis (EAMG) in rats. Using classical techniques for recording intracellular electrical events at the neuromuscular junction, we analyze synaptic transmission in intercostal muscle from patients with myasthenia, and from rat nerve-muscle preparations. We are currently examining the effects of changes in the external ionic medium on the release of transmitter in EAMG, and the developing neuromuscular defect following the transfer of serum from patients with myasthenia to rats. The effects of corticosteroids, 4-amino pyridine, d-penicillamine and aminoglycoside antibiotics on normal and myasthenic muscle are also being investigated.